Double hook type crane structure



Oct. 29, 1957 D. A. SCHAITBERGER 2,811,262

DOUBLE HOOK TYPE CRANE STRUCTURE Filed June 9, 1955 2 SheetsSheet 1 n INVENTOR.

+ DANIEL A. SCHAITBERGER ATTORNE S D. A. SCHAITBERGER 2,811,262

Oct. 29, 1957 DOUBLE HOOK TYPE CRANE STRUCTURE 2 Sheets-Sheet 2 Filed June 9, 1955 FIG.3.

INVENTOR.

DANIEL A SCHAITBERGER United states Patent 2,811,262. DOUBLE HOOK TYPE CRANE STRUCTURE Daniel, A. Schaitberger, Grosse Pointe, Mich., assignor to Northern Engineering Works, Detroit, Mich., a corporation of Michigan Applicationlune 9, 1953, SerialNo. 360,432- a 8 Claims. (Cl. 212-126) This invention relates generally to. cranes and refers more particularly to improvements' in double hook cranes.

In the manufacture of double hook cranes, it has been the practice to provide a separate hoisting mechanism for each hook and in many instances the primary'purpose of the second hoisting mechanism is to enable varying the. elevation of tilting a relatively long work object suspended from the books. For example in the manufacture of products such as lengths of tubing or pipes, it is frequently necessary to dip the product into a treating bath, andit is desirable to. tilt the product subsequent to-lifting the same out of the bathso. that anyliquid retained by the product may drain back into the bath before the product is conveyed from the. bath. In such instances, two hoisting mechanisms are not actually required to lift the load but are merely provided to enable tilting the product for the purpose stated above.

In installations of the above type, the cost of the second hoisting mechanism along with the necessary controls'is substantial and moreover operation of both hoists iscomplicated due to. the necessity of manipulating two sets of controlstion to provide a double hook crane having provision for moving one. hook relative to the other to tiltthe work object suspended from. the hooks by using a single hoistone hook relative to the other-to permit With this in view, it is an object of this invening mechanism which not only simplifies and reduces the cost of, the crane structure but, in addition, facilitates handling of the work by the crane. Moreover, elimination of onev of the: hoisting mechanisms materially reduces the overall weight of the crane and this is of prime importance especially when it is considered that the crane is; supported by the building structure at a substantial distance above. the floor.

The foregoing, as well as other objects, will be made more apparent as. this description proceeds especially when considered in connectio with the accompanying drawings, wherein:

Figure l is. a side. elevational view partly in section of a part, of a crane structure embodying the features of this invention; g 1

Figure 2; is a semi-diagrammatic'plan viewof the structure. shown in Figure 1; a

Figure. 3, is a view similar to Figure l of the. opposite side of the crane and having certain parts broken away for the sake of clearness;

Figure 4 is a sectional view of the speed reducer;

Figure 5 is, a sectional view taken, on the line. 5-5 on Figure 2'; and" 1 Figure 6 is a sectional view taken on the line. 6-6, of Figure 3'.

The crane structure selected herein for the purpose of illustration comprises a trolley 10, a track 11 for the trolley, and hoisting mechanism 12. .The trolley 10 has a supporting frame 13 comprising end members 14 and cross members 15 secured at the opposite ends thereof to the members 14 in lateral spaced relationship. Suitably mounted on the trolley frame 13 at opposite ends mounted on av shaft 29 for rotation about thereof are wheels 16 arranged to engage the track 11. The track 11 comprises laterally spaced rails 17 I-shaped incross section and secured to suitable supporting frame work 18 in positions to be respetttively engaged by the wheels at opposite ends of the trolley 10. If desired, one or more of the wheels on the trolley 10 may be driven by power means mounted on the trolley and not shown herein.

The hoisting mechanism 12 has a pair of axially aligned drums 19 and 20 secured to a drive shaft 21 in spaced relationship axially of the drive shaft. The shaft 21 extends lengthwise of the trolley 10 and is journaled in bearings 22 which are suitably secured to the trolley frame 13 at opposite ends of the drums. One end of the shaft 21 is connected to the driving shaft of an electric motor 23 by suitable reduction gearing 24 which along with the. motor 23 is mounted on the trolley 10 for movement; as a unit with the latter. A magnetic brake device 25: is also mounted on the trolley 10 and is connected to the electric motor 23 in a manner to control operation of the hoisting drums .in accordance with conventional practice. The specific driving connection between the electric motor 23 and the shaft 21 forms no part of the present invention and therefore is not disclosed in detail herein. Itxwill suffice to point out that both hoisting drums on the .trolley 20 are driven by a single electric motor 23'.

Mountedon the trolley frame 13 is-an endless chain 26. which extends substantially parallel to the drive shaft 21 between the hoisting drums and which extends around suitable sprockets 27 and 28.. The sprocket '27 is an axis extending perpendicular tov the axis of: the shaft 21 and: the sprocket 2.8'is secured; to .a; power outputshaft 30- of a speed reducer"3 1'.i The shaft 30 extendsv parallell'to the shaft 29' and is driven through the speed reducer 31 by an electric motor 32. As shownin 'Figure'4fof' the draw ings, the speed, reducer $1 comprises'a'w'orm 33 secured to the drive shaft 34 of the motor 352. and a worm. wheel 35 secured to the. shaft. 30. The; moton32 is. of: thereversible type and thereby enables driving the chain. 26 in opposite. directions. i

A flexible linear member or cable 36 has its mid; portion connected to. the bottom. run of the chain '26 between; the. sprockets by a clamp 38.. The, cable 36 is illustrated as a single continuous member and consists. of the portions or elements 37 and; 37' extending from Opposite sides of the clamp. It is apparent that the cable elements. 37 and 37' might also. be: separate membershaving their adjacent ends connected to the clamp 38.: The; cable element 37' extends from the clamp 38. over" a. guide pulley 39 and. projects downwardly from the guide pulley 39 around the-underside of a sheave 40.. From the sheave 40 the cable element 37 is; extended upwardly and is reeved or wound around the; hoisting drum 19. The cable element- 37 extendsfrom the clamp:

conditions. of. operation t-he hooks 43 are-supported at; the: same or. substantially the, same; elevation; Seth-at the;

tube or pipe 44 assumes a horizontal position beneath the trolley 10. The tube or pipe 44 may be raised or lowered while suspended from the trolley 10 in a substantially horizontal position by manipulating the hoist ing mechanism 12 in accordance with theusual practice. However, should it be desirable to elevate one hook relative to the other, or in other words, to tilt the tube or pipe suspended from the hooks,,the operator. starts :the electric motor 32 to etfect'moveme'nt ofythe ehain;26. The direction of rotation of the motor,32 determines which of the hooks43 is raised relative. to' the' other hook. Inthis connection, attention; is again directed to Figure l of the drawings wherein it will begnoted that a switch 45 is supported, below one end of the trolley in a convenient position for manipulation by the operator. The switch 45 has two control buttons which respectively start the electric motor 32 and reverse the direction, of rotation of said motor. A'similar. switch 46 is located at the opposite end of' the trolley 10 so that the electric motor 32 may be conveniently controlled from either side of the path of travel of the trolley .10.

A pair of limit switches 47 and 48 are secured to the trolley frame 13 adjacent the bottom run of the chain 26 for operation by engagement with the clamp 38. The purpose of the limit switches 47 and 48 is to automatically stop the electric motor 32 before the clamp 38 engages either of the sprockets 27 and 28.

The electrical system is such that closing of the circuit to the motor 32 causes the chain 26 to travel in one direction around the sprockets 27 and 28. As the clamp 38 is advanced in the aforesaid direction by the chain 26, the cable elements are operated to raise one hook 43 and to lower the other hook so that the pipe or tube suspended from the hooks is tilted. However, the extent of travel of the chain 26 is definitely limited by engagement of the clamp 38 with one of the limit switches which is positioned on the trolley 10 to stop the motor 32 at the required point. The tube or pipe 44 may be restored to its original position by reversing the direction of rotation of the motor 32 with the result that the clamp 38 on the bottom run of the chain 26 is moved in a direction opposite the direction aforesaid. The extent of return travel of the clamp 38 is determined by the position of the second limit switch on the trolley 10 which when engaged by the clamp 38 again stops the electric motor 32. It is apparent from the foregoing that the elevation of the hooks may be very accurately controlled by predeterrnining the location of the limit switches with respect to each other on the trolley 10. Ifdesired, one of the limit switches may be positioned to assure stopping the electric motor 32 when the hooks 43 are at the same or substantially the same elevation. I

What I claim as my invention is:

1. A crane comprising supporting structure, a pair of drums rotatablymounted on the supporting structure in spaced relation to each other, a hoisting mechanism op-- eratively connected to the drums for rotating the latter, a pair of sheaves respectively positioned below the drums,

flexible linear elements respectively reeved around the drums and having portions extending downwardly from the drums beneath the respective sheaves, a member connected to the linear elementsbetween the sheaves and mounted on the supporting structure for movement in opposite directions toward and away from the sheaves to change the elevation'of one sheave relative to the other, power means carried by the supporting structure and operatively connected to the member for moving the latter in opposite directions, and means respectively supported by the sheaves and attachable to an elongated object at points spaced from each other lengthwise of the object.

2. The structure defined in claim 1 wherein the pair of drums are secured to a drive shaft in spaced relation to each other axially of said shaft and wherein the hoisting mechanism comprises an electric motor operatively conand reversing the direction of rotation thereof.

5. A crane comprising supporting structure, a pair of drums rotatably mounted on the supporting structure in spaced relation to each other, a single hoisting mechanism connected to both drums for rotating the latter, first and second sheaves respectively positioned below the drums,

carried by the sheaves.

flexible linear means having portions respectively reeved around the drums and having portions extending around the undersides of the sheaves in supporting engagement therewith, a pair of spaced wheels mounted on said supporting structure and having a flexible endless linear member extending around said wheels, power operated means operatively connected to one of said wheels to drive said member in opposite directions, means connecting one side of said member to the flexible linear means between said sheaves whereby movement of said member in one direction raises the first sheave relative to the second sheaveand movement of said member in the opposite direction lowers the first sheave relative to the second sheave, and work supporting means respectively I 6. The structure defined in claim 5 wherein the hoisting drums are secured to a common drive shaft in spaced relation to each other axially of the shaft, and wherein said member extends in the general direction of length of I the shaft.

' eratively connected to said drums for rotating the latter,

a. pair of sheaves respectively positioned below said drums, flexible linear elements respectively reeved around said drums and extending downwardly from said drums at one side of said respective sheaves beneath the latter and then extending from said sheaves at the other side of the latter, a member connected to the portions of said linear elements which extend from said sheaves at the said other side thereof, said member being movable in opposite directions relative to said sheaves to change the elevation of one sheave relative to the other, power means operable independently of said hoisting mechanism for moving said member in opposite directions, and work supporting means respectively carried by said sheaves.

References Cited in the filepof this patent UNITED STATES PATENTS 

